Band pass filter 2nd order

R1 = R2 = 0.5*R3 = R;

C1 = C2 = C;

Center frequency = 1/(2*pi*R*C);

Inner gain = 1 + (R5/R4) = G;

Gain at center frequency = G/(3 – G);

filter quality Q = 1/(3 – G);

Band width = # * center frequency/Q ? (can be tuned)

Case 1:

R1 = R2 = 0.5*R3 = 15.9K; C1 = C2 = 0.1n; R4 = R5 = 1k;

Fc = 100KHz; Inner gain = 2; Gain at Fc = 2; Q = 1; Band width = #*100KHz?

Case 2:

R1 = R2 = 0.5*R3 = 15.9K; C1 = C2 = 10n; R4 = R5 = 1k;

Fc = 1KHz; Inner gain = 2; Gain at Fc = 2; Q = 1; Band width = #*1KHz?

Case 3:

R1 = R2 = 0.5*R3 = 15.9K; C1 = C2 = 1n; R4 = R5 = 1k;

Fc = 10KHz; Inner gain = 2; Gain at Fc = 2; Q = 1; Band width = #*10KHz?

Case 4:

R1 = R2 = 0.5*R3 = 15.9K; C1 = C2 = 1n; R4 = 1K; R5 = 0k;

Fc = 10KHz; Inner gain = 1; Gain at Fc = 0.5; Q = 0.5; Band width =#* 20KHz?

Case 5:

R1 = R2 = 0.5*R3 = 15.9K; C1 = C2 = 1n; R4 = 1K; R5 = 0.5k;

Fc = 10KHz; Inner gain = 1.5; Gain at Fc = 1; Q = 0.667; Band width =#* 15KHz?

Case 6:

R1 = R2 = 0.5*R3 = 15.9K; C1 = C2 = 1n; R4 = 1K; R5 = 1.5k;

Fc = 10KHz; Inner gain = 2.5; Gain at Fc = 5; Q = 2; Band width =#* 5KHz?

 

Case 7:

R1 = R2 = 0.5*R3 = 15.9K; C1 = C2 = 1n; R4 = 1K; R5 = 2k;

Fc = 10KHz; Inner gain = 3; Gain at Fc = infinity; Q = infinity; Band width = 0Hz.

Case 8:

R1 = R2 = 0.5*R3 = 15.9K; C1 = C2 = 1n; R4 = 1K; R5 = 2.5k;

Fc = 10KHz; Inner gain = 3.5; Gain at Fc = -7; Q = -2; Band width = -#*20kHz?

Case 9:

R1 = R2 = 0.5*R3 = 15.9K; C1 = C2 = 1n; R4 = 1K; R5 = 100k;

Fc = 10KHz; Inner gain = 100k; Gain at Fc = -1; Q = -1e-5; Band width = -#*100MHz?